Cone crushers are used for crushing large rock into small rock or gravel such as used for road beds. A fixed liner forms a conical-shaped cover under which a conical-shaped cone is gyrated in a circular or rolling action. The cone is moved in a circular pattern such that the peripheral surface of the cone moves in close proximity along the inner circumferential surface of the liner. Material flowing between the liner and cone is crushed by the movement of the cone relative to the liner. The rolling action is achieved by orienting the cone to have an axis at a slight angle from vertical and then applying a gyrating movement whereby the offset axis is rotated around the fixed vertical axis of the liner, e.g., at a rate of 300 rpm.
The rotation of the offset axis is achieved by a cylinder-like support referred to as a wedge plate that rotates around the axis of the machine (also the axis of the liner). The cone has a center shaft and the cone and its shaft are symmetrical relative to the cone axis. The wedge plate confines the cone shaft within roller bearings that establish the axial position of the cone shaft at an offset relative to the wedge plate's axis of rotation. Rotation of the wedge plate thereby generates a rotation of the offset axis of the cone around the axis of the machine. The wedge plate is rotated at about 300 rpm and, therefore, the rotation of the cone's axis is also at 300 rpm. However, the cone itself does not rotate with the wedge plate and essentially rolls along the inner surface of the liner.
The cone as explained is substantially symmetrical relative to its axis but by offsetting that axis, the weight of the cone is unbalanced relative to the axis of rotation. The unbalanced weight sets up undesired vibration. To balance the offset weight of the cone, weight is added to one side of the wedge plate, i.e., opposite the offset axis. Whereas the offset weight of the cone can be calculated, the offsetting weight to be added to the wedge plate can be somewhat determined and that added weight can be provided in the basic design of the wedge plate. However, there are too many variables to achieve a balance that is fully satisfactory and a fine tuning of the weight distribution is necessary for each machine after final assembly.
Heretofore it was common to simply add weights to the wedge plate exterior, e.g., the weights were bolted onto the wedge plate. This process is time consuming and leaves the weight exposed to the crushed rock passing through the crusher which can erode or wear away at the weights and require replacement.